1. Combine lemon peel and agave in a shallow dish. Dip the rim of each glass into mixture. Freeze until ready to serve. 2. Bring water to a boil in a large pot. In a bowl, combine hibiscus blossoms, cloves, cinnamon stick, and vanilla pod. Add to boiling water and boil for 1 minute, stirring. Remove from heat and stir in honey. Let steep for 1 hour. 3. Strain mixture into a pitcher, pressing on blossoms to extract all juices. Refrigerate until cold, or overnight. Pour into prepared glasses and serve.